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Old Jan 07, 2013, 07:10 AM
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Future Wingz's Avatar
United States, WA, Seattle
Joined Aug 2012
73 Posts
Quote:
Originally Posted by Pannoch RC View Post
Its been a while but I finally maidened mine on Saturday. The flight was exciting so say the least. The RHS flap hung slightly lower than the LHS causing a constant roll to the left which was manageable but required concentration.
The current draw was huge, setting off the LVC after only 2 min of flight. This also heated the battery connection to the point where the solder melted. Only the heat shrink kept the cable to the connector which finally separated on landing.
I didn't quite make it back to the strip, landing in a field which only caused minor bending to the landing gear. Otherwise not a scratch.
I've already fixed the retracts and I'm in the process of designing a better wiring system to handle the current flow, and looking for bigger batteries. I used a 14.8V 5000mah Nanotec for the flight which proved to be powerfull enough, just not enough capacity.

Easily takes off from grass with flap and spoiler mod. Inboard cam shows very little wing flex which was put through its paces due to the flap induced roll

Here's the vid

http://www.youtube.com/watch?v=JbgIZ-7m-rw

Cheers



Paul
Great job! on your maiden Paul, hopefully, you can get that landed gear sorted. No maiden on the Ethiopian in sight yet as we are currently in the thick of the bad weather season.

Cheers

Vic
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Old Jan 07, 2013, 07:35 AM
Registered User
wisconsin
Joined Feb 2004
166 Posts
Glad to hear it flew Paul....
You are scarring me on something.
I am running the same motor and batteries as you are.
However I am using 12 gauge wire.
Please let us no what you are planning on doing to solve your problem.
Same as Vic,, Winter is here in southern Wisconsin. Still waiting for spring to do the maiden

Hoss
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Old Jan 07, 2013, 11:53 AM
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jurgen01's Avatar
Mexico City
Joined Apr 2007
333 Posts
Congrats Paul, after all a sucessful flight. A good flight is when you can use the plane again.
The inboard vid is kind of scary at the very end. First there is music and engine sound, then just music and the crash noise and then absolute silence. Bonus scene (not in the original video): someone moves and asks into the loud silence 'Everybody OK?'

I cannot see well in the video, but it looks like you are using 4mm connectors. On my plane I used 6mm bullet connectors from HK between the battery and the Y. They worked fine at a total of 107A.
After the Y I use Deans ultra plug connectors for each ESC which work fine at 53A per fan.
Did you check your current consumption?

Regards Jurgen
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Last edited by jurgen01; Jan 07, 2013 at 12:07 PM.
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Old Jan 07, 2013, 05:28 PM
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Doug W's Avatar
United States, WA, Seattle
Joined Jul 2010
481 Posts
Quote:
Originally Posted by Future Wingz View Post
Great job! on your maiden Paul, hopefully, you can get that landed gear sorted. No maiden on the Ethiopian in sight yet as we are currently in the thick of the bad weather season.

Cheers

Vic
You're telling me Vic!! This weather is awful! (Got your text the other day- Happy New Year!!)
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Old Jan 07, 2013, 05:30 PM
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Doug W's Avatar
United States, WA, Seattle
Joined Jul 2010
481 Posts
Quote:
Originally Posted by Pannoch RC View Post
Its been a while but I finally maidened mine on Saturday. The flight was exciting so say the least. The RHS flap hung slightly lower than the LHS causing a constant roll to the left which was manageable but required concentration.
The current draw was huge, setting off the LVC after only 2 min of flight. This also heated the battery connection to the point where the solder melted. Only the heat shrink kept the cable to the connector which finally separated on landing.
I didn't quite make it back to the strip, landing in a field which only caused minor bending to the landing gear. Otherwise not a scratch.
I've already fixed the retracts and I'm in the process of designing a better wiring system to handle the current flow, and looking for bigger batteries. I used a 14.8V 5000mah Nanotec for the flight which proved to be powerfull enough, just not enough capacity.

Easily takes off from grass with flap and spoiler mod. Inboard cam shows very little wing flex which was put through its paces due to the flap induced roll

Here's the vid

http://www.youtube.com/watch?v=JbgIZ-7m-rw

Cheers

Paul
Nice job Paul!! Congrats on the maiden- sorry to hear of the flap rigging issue- I had a similar issue on my maiden of the Alaska untilIi trimmed it and ultimately re-rigged one of the flaps. For some reason, the Wedgetail was rock solid and has since required zero roll trim for flap rigging.
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Old Jan 08, 2013, 12:23 AM
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Hawaiian Flyin's Avatar
Maui, Hawaii
Joined Dec 2007
326 Posts
Paul;
Check out Spyro's build. He has a diagram of how he wired his. I had similar current draw problems with mine. Melted solder and I only got a little over 2 minutes of run time while testing on the bench. I had used 14 gauge wire. Wired it up like Spyro showed and used 10 gauge wire and I got almost 6 minutes at about 2/3 throttle before I turned it off. That was bench testing with 2 4S 4000 batteries. I'm no expert having flown mine only once. Only had it airborne for a little over 2 minutes but landed it intentionally because my hands were shaking too much! But wiring it up like Spyro did had a significant improvement. Good luck!
Hawaiian
Also just got done modifying the landing gear with the 4mm shafts. Found out the stock 3mm shafts are not steel but aluminum. No wonder they bent!
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Old Jan 08, 2013, 03:46 AM
Paul B
Australia, TAS, Launceston
Joined Dec 2009
352 Posts
Thanks guys for all the hints.
I've received feedback from the manufacturer of my EDF combo's. I carried out some checks. Individually, the EDF's pull 65A each and develope just on 950W (as per the manufacturers predictions). But when connected together as they were in the flight, they only pull 99A combined and just on 1350W.
I used genuine Deans plugs, which are rated at around 80A, and 10AWG cable. Obviously, they will handle around a maximum of 99A from my pratical exercise. The rest was lost as heat, hence the melting of the solder and fusing of the Deans connector.

Now I am using 8 AWG cable and 6.5mm bullet connectors rated at 150A and a minimum battery setup of 2x 4s 4400mah lipos. Just waiting for the connectors to arrive.
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Old Jan 08, 2013, 04:55 AM
Paul B
Australia, TAS, Launceston
Joined Dec 2009
352 Posts
Quote:
Originally Posted by Hawaiian Flyin View Post
Paul;
Check out Spyro's build. He has a diagram of how he wired his. I had similar current draw problems with mine. Melted solder and I only got a little over 2 minutes of run time while testing on the bench. I had used 14 gauge wire. Wired it up like Spyro showed and used 10 gauge wire and I got almost 6 minutes at about 2/3 throttle before I turned it off. That was bench testing with 2 4S 4000 batteries. I'm no expert having flown mine only once. Only had it airborne for a little over 2 minutes but landed it intentionally because my hands were shaking too much! But wiring it up like Spyro did had a significant improvement. Good luck!
Hawaiian
Also just got done modifying the landing gear with the 4mm shafts. Found out the stock 3mm shafts are not steel but aluminum. No wonder they bent!
I think I will follow Spyro's lead with the wiring, just ordered the 4mm shafts as well.

Hi Doug, I've just finished re-programming the flaps so now they move the same amount. The difference wasn't huge but it was certainly noticed in the air!!

For what its worth, I added to the wing a 1mm x 6mm carbon spar through its entire length, and I also added a 3.5mm carbon tube spar in each horizontal stabilizer.

This plane is so forgiving when out of trim

Cheers

Paul
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Old Jan 08, 2013, 05:00 AM
Registered User
United States, CA, Pasadena
Joined Jun 2007
221 Posts
My windrider 737 is still sitting in customs for inspection. It has been there since Jan 2nd 2013, is this normal? Has anybody else had this problem or is it just my order?
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Old Jan 08, 2013, 05:05 AM
The sky is the limit
BAF23's Avatar
Belgium, Vlaams Gewest, Hasselt
Joined Aug 2012
197 Posts
battery heat

I got seriously alarmed by seeing and reading about the heat development but am puzzled about solutions. I understand thicker wires and better plugs will save the day, but looking at my (still to be build) model I wonder if ventilating the fuselage might not help as well. Batteries develop heat and cables as well, but there is no way out for that heat in that temperature isolated foam fuselage, it will just keep accumulating.

When I will build mine in a few months (other projects underway), I'll definitely make cheater holes to at least evacuate the heat during flight. Looking at the pictures of the original it is obvious the two exhausts in the tail (for the APU) seem ideal candidates. The main gear wheels wells are large but mostly blocked during flight (I plan on main gear doors and nose wheel doors on mine). The NACA intakes at the wing roots can easily be opened up and airflow guided to the battery(ies). Some guys open up windows for camera shooting, why not open just a couple for cooling as well? using the emergency exit ones will even allow you to get a rod through to balance the airplane.

Reading those latest flight experiences I'm even more tempted to use separate 4or5s batteries for each HK2855-2100kva engine with CS10fan.
Thanks everybody for sharing of all the very useful practical information and your flight experiences. I'm Looking forward to join you soon in the pleasures.
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Old Jan 08, 2013, 06:21 AM
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Future Wingz's Avatar
United States, WA, Seattle
Joined Aug 2012
73 Posts
Quote:
Originally Posted by Pannoch RC View Post
I think I will follow Spyro's lead with the wiring, just ordered the 4mm shafts as well.

Hi Doug, I've just finished re-programming the flaps so now they move the same amount. The difference wasn't huge but it was certainly noticed in the air!!

For what its worth, I added to the wing a 1mm x 6mm carbon spar through its entire length, and I also added a 3.5mm carbon tube spar in each horizontal stabilizer.

This plane is so forgiving when out of trim

Cheers

Paul
Hi Paul, I also went with Sypro's recommendation for wiring up (2x) 4400 4S packs although in retrospect, I probably only needed 1 pack. Anyway the capability to run a 2 pack config is there should I need it. Not sure if I opted for the 8AWGs instead of the 10AWG. I'll need to check. Chief Flaps Officer Doug has been helping me fine tune the flaps He's got the this thing down to a science. With lessons learned from the maiden, I am confident you'll have all these issues sorted soon.

Cheers

Vic
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Old Jan 08, 2013, 10:18 AM
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Cocg's Avatar
United States, CO, Grand Junction
Joined May 2010
2,325 Posts
Quote:
Originally Posted by 8492ND View Post
My windrider 737 is still sitting in customs for inspection. It has been there since Jan 2nd 2013, is this normal? Has anybody else had this problem or is it just my order?
I have found often (not always) from overseas shipping the tracking ends at customs... It will say read "in customs" yet be at my door... Not to worry..!!
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Old Jan 08, 2013, 10:52 AM
Registered User
wisconsin
Joined Feb 2004
166 Posts
Customs......

Quote:
Originally Posted by 8492ND View Post
My windrider 737 is still sitting in customs for inspection. It has been there since Jan 2nd 2013, is this normal? Has anybody else had this problem or is it just my order?
I just recieved my turbine jet from China.
1 week in customs in China and 2 weeks in customs in Chicago.
As I understand,, they are in no huury.
Don't worry You will get it

Good Luck

Hoss
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Old Jan 08, 2013, 11:21 AM
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Highfly!'s Avatar
United States, CA, Cameron Park
Joined May 2007
1,259 Posts
I have been flying a variety of twins including the 737 and have always used separate packs for each motor mainly to avoid situations as some of you have experienced. Important though is that both packs are charged in sync and are more or less from the same batch to reduce in-even discharge. As an additional precaution you can wire them in parallel which in the case of the 737 is easy to do.
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Old Jan 08, 2013, 01:30 PM
Registered User
United States, TX, League City
Joined Jun 2008
368 Posts
Thrust reversers

After numerous attempts at making a cascade reverser I think I've finally found the most efficient/effective design

Previous attempts resulted in catastrophic failures due to the plates not being able to withstand the thrust from the edf and or possibilities of restricting and coming loose during flight in the engine pylon.

After weeks of tinkering I've decided to make a more complex structure with CF rods tubes and push/pull wires with guide vanes for control running through the wings (awaiting new 737 to arrive for this) and develope a more structural design so no inflight mishaps are possible.

In the video shown here I've placed some tape on the inlet to show intake direction and then half throttle to show reverse direction/efficiency. It's yielding a good 80% thrust deflect forward so far until I perfect the mechanism to fully swivel freely/block air flow

Here's the demo video:
Rc 737 thrust reverse beta test 7 (0 min 12 sec)


These will be wired in conjunction with the spoilers and slide open/close with a toggle switch. The plates that block the exit of the engine to redirect thrust will be some precise wires/tubes/hinges. VERY tedious so far but I think the final product will be one of a kind

Stay tuned for LE slats
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